Demonstrating error rate homogenization using dynamically corrected gates in a trapped ion system

High quality, error-robust gates are a fundamental element of scalable quantum computing architectures; however, their performance is often limited by their high sensitivity to external perturbations and imperfections in the control field. We experimentally demonstrate that replacing “primitive” physical gates with error-suppressing, dynamically corrected gates (DCGs) can homogenize error rates across a qubit register in both space and time, in addition to reducing net error rates.
We perform parallel single-qubit operations on a multi-qubit register of ¹⁷¹Yb⁺ ions using a microwave field. We achieve a best case single-qubit average error rate of 1.9e-5 using primitive gates, although inhomogeneous fields lead to an order of magnitude variation across the 10 qubit register. By using DCGs, we observe an 8.5x reduction in the spread of error rates across the register, and a 2.4x improvement of the average value. Furthermore, DCGs provide an added robustness to slow drifts in the control, reducing the overhead required for regular calibrations.
Finally, we discuss a microwave synthesis chain using a cryogenic sapphire oscillator and an arbitrary waveform generator, aimed at improving the control-field phase noise and reducing the calibration requirements compared to traditional I/Q.